At Arkansas, the six-foot (1.83 m), 180-pound (82 kg) Alworth was a flanker[3] who led all colleges in punt return yardage in 1960 and 1961. He also was a track star, running the 100 and 220-yard dashes (in 9.6 seconds and 21.2 seconds, respectively) and long jump.[3] Alworth was a three-time Academic All-American, graduating with a degree in marketing as a pre-law student.[3] In 1962, Alworth was on multiple All-American teams: Look magazine, Associated Press, United Press International and Coaches.[3] He is a member of the Pi Kappa Alphafraternity. Alworth is a member of the University of Arkansas Hall of Honor and the Arkansas Sports Hall of Fame; he was named to the University of Arkansas' 1960's All-Decade Team, and the school's All-Century Team in 1994.

In his rookie season, Alworth had just 10 receptions in 4 games (though three were for touchdowns). His second year was a different story, as he set franchise records in receptions (61), yards (1,205), and touchdowns (11),[6] earning the UPI's AFL Most Valuable Player award. He had 4 receptions for 77 yards, including a 48-yard touchdown, in San Diego's AFL championship win over the Boston Patriots. He was selected as an AFL Western Division All-Star for the first of seven consecutive seasons, as well as an AFL All-League flanker for the first of six seasons, selected by his peers from 1963 to 1966, and by newspaper wire services from 1967 to 1968.

Over the next six seasons (1964-69), Alworth broke his own franchise receiving records several times, and also led the league in receptions, receiving yards, receiving touchdowns, and total touchdowns three times each. He shattered the record for most consecutive seasons with over 1,000 receiving yards (7, previously 3, now held by Jerry Rice with 11), and was the first player with back-to-back seasons averaging 100+ receiving yards per game, both of which led the league.[7] The 1966 season was particularly noteworthy, because he led the league in five categories. He still shares the record for the most regular season games with 200+ yards receiving (5),[8] and had a franchise-record streak of 96 consecutive games with a reception. Alworth formed a formidable tandem with Chargers quarterbackJohn Hadl, and is considered by many to be the best wide receiver in all professional football during the 1960s. He is a member of the AFL All-Time Team. He was the first of only a few American Football League stars to be featured on the cover of Sports Illustrated,[9] which like other media of the 1960s, showed a distinct bias for the NFL. Sports Illustrated even went so far as to declare Alworth the "Top Pro Receiver", this at a time when many[who?] claimed the AFL had inferior players. 1970 saw a sharp decline in Alworth's productivity (35 catches for 608 yards), and he was traded to Dallas at the end of the season. See below for his numerous franchise records with the Chargers.

In Super Bowl VI following the 1971 season, he scored the game's first touchdown, which was a 7-yard touchdown pass from Roger Staubach in the Cowboys' 24-3 victory over the Miami Dolphins.[11] Alworth would later call the two receptions he made in Super Bowl VI (one that converted a third and long and the other for the touchdown) the two most important catches of his career.

In 1999, he was ranked number 31 on The Sporting News' list of the 100 Greatest Football Players, making him the highest-ranking Charger and the highest-ranking player to have spent more than one season in the AFL.

In 2014, he was inducted into the Southwest Conference Hall of Fame.[15]